Double hook door mechanism

ABSTRACT

The present invention provides a double hook door mechanism for use in opening and closing aircraft landing gear bay doors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/630,507,filed Dec. 3, 2009 (Attorney Docket No. T8472898US1) which claims thebenefit of Provisional Application No. 61/193,530, filed Dec. 5, 2008,all of which are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to a door mechanism used to open and closeaircraft landing gear doors. In particular the present invention relatesto a double hook door mechanism for use in opening and closing aircraftlanding gear doors.

BACKGROUND OF THE INVENTION

Landing gear doors, located on aircraft, are configured to open andclose to allow for the raising and lowering of landing gear during takeoff and landing. To date, either independent actuators or a series oflinkages or a hook that is mounted on the landing gear doors have beenused to operate the opening of the landing gear doors.

When independent actuators are used they are generally mounted on theforward bulkhead of the landing gear bay and will allow the landing geardoors to be opened and closed when the nose landing gear is raised andlowered. However, the increased weight of the actuators and theassociated equipment that is used can cause a problem dues to the addedweight and complexity of the equipment which can be unacceptable in theaircraft system. In addition, there is a general desire to move awayfrom the use of hydraulic components within the industry.

Alternatively, a series of linkages may be used that are driven by themain fitting or drag brace. However, such use can be difficult to designand is not always available as an option for all landing gear. Inaddition, the use of such linkages does not allow the landing gear doorsto be closed when the landing gear is extended and therefore cansignificantly decrease the aerodynamics of the aircraft.

The use of a hook on the door of the landing gear bay requires verylarge and expensive springs to keep the door in place. In addition, theuse of hooks does not generally allow the doors to be closed when thelanding gear is extended which, as mentioned above, will be detrimentalto the aerodynamics of the aircraft.

It is therefore desirable to provide a mechanism that allows the landinggear doors to be opened and closed without sacrificing the aerodynamicsof the aircraft and without requiring the use of expensive components.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a door mechanism, for usein opening and closing aircraft landing gear doors, which does notsacrifice the aerodynamics of the aircraft.

In another aspect, the present invention provides a double hook doormechanism, for use in opening and closing aircraft landing gear doors.

In one embodiment the present invention provides a double hook doormechanism that includes two hooks that are configured to act in tandemwith each other and to rotate in opposing directions to each other. Thefirst hook being configured to close the doors as the landing gear isretracted into the landing gear bay and the second hook being configuredto re-close the doors as the landing gear extends.

There is also provided a door mechanism for use on an aircraft landinggear door comprising first and second hooks configured to operate intandem with each other and to rotate in opposing directions, the hooksbeing configured to open and close the landing gear door as the landinggear extends and retracts. The first hook is configured to close thelanding gear door when the landing gear is retracted and the second hookis configured to re-close the doors as the landing gear extends.

There is also provided an aircraft landing gear assembly comprisinglanding gear, moveable between a retracted and an extended position,including an upper drag brace having a projection extending therefrom; alanding gear bay configured to receive the landing gear when it is inthe retracted position, the landing gear bay comprising a plurality ofdoors moveable between open positions and closed positions; a pluralityof door mechanisms, each door mechanism connected to a respective door,each door mechanism comprising at least two hook portions connected toeach other and configured to simultaneously rotate in opposingdirections, rotation of the hook portions being effective to open andclose the doors, each hook portion configured to releasably connect withthe projection on the landing gear while the landing gear is movingbetween the extended and retracted positions; the movement of thelanding gear initiating contact of the projection with one of the hookportions which causes the hook portion to rotate.

There is also provided a door mechanism for use on an aircraft landinggear bay door, the landing gear including an upper drag brace having aprojection extending therefrom, the door mechanism comprising a firsthook connected to the aircraft airframe at a first connection point andconfigured to rotate about the first connection point; and a second hookconnected to the first hook and connected to the aircraft airframe at asecond connection point and configured to rotate about the secondconnection point, one of the first and second hooks being connected tothe door wherein the first and second hooks are configured tosimultaneously rotate in opposing directions wherein rotation in a firstconfiguration opens the landing gear door and rotation in a secondconfiguration closes the landing gear door.

In one embodiment the first and second hook are connected to each otherby a rod and the second hook is connected to the door. In anotherembodiment the first hook is connected to a biasing means that applies aforce on the first hook in a first direction. In another embodiment,each of the first and second hooks are configured to releasably connectwith the projection on the upper drag brace

There is also provided a device for opening and closing a landing gearbay door comprising a door rod coupled to the landing gear bay door at afirst end; a first connector, pivotably coupled to the landing bay at afirst connection point and biased to pivot about the first connectionpoint in a first direction; a second connector, pivotably coupled to thelanding bay at a second connection point and coupled to the door rod atits second end; the first and second connectors coupled to each otherand configured to simultaneously rotate in opposing directions, thefirst and second connectors configured to independently engage with aprojection located on the landing gear, engagement of one of the firstand second connectors with the projection causing rotation of theconnectors which translates to movement of the door rod to open or closethe bay door.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in further detail below withreference to the accompanying drawings in which:

FIG. 1 illustrates one embodiment of the double hook door mechanism ofthe present invention;

FIG. 2 is a schematic of one embodiment of the double hook doormechanism of the present invention shown with the landing gear extended;

FIG. 3 is a schematic of one embodiment of the double hook doormechanism of the present invention showing the landing gear retracting;

FIG. 4 is a schematic of one embodiment of the double hook doormechanism of the present invention shown with the gears refracted;

FIG. 5 is a schematic of the double hook door mechanism of FIG. 2showing the landing gear bay and a portion of the aircraft;

FIG. 6 is a schematic of the double hook door mechanism of FIG. 3showing the landing gear bay and a portion of the aircraft; and

FIG. 7 is a schematic of the double hook door mechanism of FIG. 4showing the landing gear bay and a portion of the aircraft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a double hook door mechanism for use inaircraft landing gear doors that efficiently opens and closes the doorswhile maintaining the aerodynamics of the aircraft.

The double hook door mechanism of the present invention includes the useof two hooks that act together to open and close the landing gear doors.It will be understood that the description provided herein relates toone of the doors of the landing gear bay and one door mechanism that isconnected to that door. However, it will be known to a person skilled inthe art that generally landing gear bays include two doors and thereforewill include two door mechanisms, one for each door. It will further beunderstood that the left hand side door mechanism is illustrated anddescribed herein. The right hand door mechanism will have the oppositeconfiguration.

The double hook door mechanism of the present invention includes twohooks that each rotate about an axes that is perpendicular to the axesof rotation of traditional mechanisms used in the field. The double hookdoor mechanism of the present invention is easier to configure and alsoallows re-closing of the door which is typically not possible.

The present invention provides a double hook door mechanism thatincludes two hooks that are configured to act in tandem to open andclose the aircraft landing gear doors. The hooks are configured torotate in opposing directions and apply a force on the landing geardoors when required to open or close them. In addition, the double hookdoor mechanism is operable to maintain the doors in an open position toallow the landing gear to extend out of the landing gear bay and thenclose the landing gear doors to allow the aerodynamics of the aircraftto be maintained.

The double hook door mechanism of the present invention will now bedescribed in further detail with reference to FIGS. 1-7.

FIG. 1 shows a portion of the landing gear, and in particular the upperdrag brace, with the double hook door mechanism shown in the foreground,and indicated generally at 10.

It will be understood that the double hook door mechanism is shown inthe Figures in use on a nose landing gear that is contained within alanding gear bay having a door that opens and closes. However, it willbe understood that the double hook door mechanism is not limited to usewith the specific landing gear that is illustrated. The double hook doormechanism of the present invention may be used in combination with anylanding gear provided that it is able to operate as described herein. Inaddition, it will be understood by a person skilled in the art thatexisting landing gears and landing gear bays may be retrofitted toinclude the double hook door mechanism of the present invention, asdescribed further below.

As can be seen in the Figures, the upper brace of the landing gear,indicated at 12, includes extending out of one side, a projection 14.The projection is also referred to herein as a roller. The projection 14extends out of the side of the upper drag brace 12 a sufficient distanceto be operable to connect with portions of the double hook doormechanism 10, as described in further detail below, to allow foroperation of the double hook door mechanism 10. The projection 14 willmove or rotate with the movement of the upper drag brace 12. Inaddition, the projection 14 is operable to rotate about its own axisseparately from the upper drag brace 12.

The projection 14 may be made from any material that is suitable towithstand the environment within which it is contained and sustain thewear from the contact with the hooks, described below. For example thematerial must be able to withstand a range of temperatures which thelanding gear bay may be exposed to. The projection 14 may be made from astandard roller or it may be built up from detailed parts. Preferablythe projection 14 is made from stainless steel. The projection 14 issized and shaped to be received by the hooks, described further below,of the double hook door mechanism 10. In addition, the projection 14must be able to withstand the hook contact load and the shear loads.

The double hook door mechanism 10, shown clearly in FIGS. 1 through 7,includes two hooks, or connectors, an upper hook 16 and a lower hook 18.The upper and lower hooks 16, 18 are configured to be able to receivethe projection 14 within each hook to allow for separate movement androtation of each hook, about the projection 14. It will be understoodthat the upper and lower hooks may be the same size and shape or maydiffer, provided that they are able to function as described herein. Theupper hook 16 is operable to close the landing gear doors when thelanding gear is retracted into the landing gear bay. The lower hook 18is operable to re-close the doors as the landing gear extends. The upperand lower hooks 16, 18, and their use, will be described in furtherdetail below.

The illustrated double hook door mechanism 10 is connected to theairframe, or landing gear bay, in three places, indicated generally bytriangles, identified at numeral T in FIG. 3. It will be understood thatthe upper drag brace 12 is also connected to the airframe at triangleT1, indicated in FIG. 3. It will be understood that the attachment ofthe double hook door mechanism 10 and the upper drag brace 12 to theairframe may be secured by any means known in the art.

The double hook door mechanism 10 includes a biasing means, or spring(s)20, which provide a door opening moment to force the landing gear baydoors open and to keep the doors open against an over-centre stop,indicated in FIG. 3 and discussed further below, when the landing gearis in transit between the gear up and gear down positions. It will beunderstood that one or more springs may be used in this position. In apreferred embodiment, two springs are used for redundancy, however thepresent invention is not limited to the use of two springs.

At the opposite end of the double hook door mechanism 10 a door rod 24connects the door mechanism 10 to the bay door of the landing gear. Atthe opposite end the door rod 24 is connected to one end of the lowerhook 18. The connection of the door rod 24 to the bay door allows thedoor mechanism 10 to open and close the bay door. The specificconnection of the door rod to the bay door is not shown, however thedoor rod 24 can be attached to the bay door using a spherical bearingwith a bolt and nut. It will be understood that the connection of thedoor rod 24 to the bay door is not limited to this type of connection,and any other connection may be used that will be known to a personskilled in the art.

The door rod 24 is pivotably connected to the lower hook 18. Theconnection may be made as described above using a spherical bearing witha bolt and nut. However, as described above, the connection is notlimited to this and other means may be used as will be known to a personskilled in the art.

Turning to the upper and lower hooks 16, 18 clearly shown in theFigures, both hooks are shaped to be able to connect with projection 14and to rotate relative to the projection 14. Both hooks 16, 18 include abody portion, upper hook body 26 and lower hook body 28 that each haveprojecting hook portions, upper hook portion 30 and lower hook portion32 that extend away from the upper and lower hook bodies 26, 28respectively. Each of the upper and lower hook portions 30, 32 are sizedand shaped to connect with the projection 14, as described furtherbelow.

Both the upper hook portion 30 and the lower hook portion 32 include twoarms, indicated at numeral 33, that form the hook shape. The upper hookportion 30 is shown with only one arm since the other is located behindthe upper hook body 26 in the Figures. The upper hook body 26 isconnected to the upper hook body 26 at position A. Likewise lower hookportion 32 is connected to lower hook body 28 at position B.

The two arms 33 located on each of the hook portions form a recessbetween them. The second, and smaller arm, on each hook portion allowsthe projection 14, or roller, to hit the second arm and force the lowerand upper hook to move if any ice build-up has seized the mechanism. Itwill be understood that during normal operating conditions the secondarm will not be used. It will be understood that other shapes and formsmay be used for the upper and lower hooks 16, 18, and in particular forthe upper and lower hook portions 30,32 and arms 33, provided that thesecomponents still function, as described herein, and are configured toconnect with projection 14.

Connecting the upper hook 16 to the lower hook 18 is a linkage rod 34.The linkage rod 34 connects the two hooks 16, 18 so that they areconfigured to act in tandem and are further configured to rotate inopposite directions. In addition, the linkage rod 34 is configured totransfer load from the upper hook 16 through the lower hook 18 to thedoor rod 24. The door rod 24, in turn, transfers the load to the door towhich it is connected so that the door may be opened or alternativelyclosed when no load is applied. In a preferred embodiment, the linkagerod 34 is connected to each end of the upper and lower hooks 16, 18using two bolts and nuts. However, it will be understood that theconnection of these parts may be made by any means known in the art andis not limited to this embodiment.

The operation of the double hook door mechanism of the present inventionwill now be described in further detail with reference to the Figures,and in particular FIGS. 2-4. As stated above the Figures illustrate anose landing gear and show the left hand door of the nose landing gearbay. As described above, the right hand door will include a doormechanism that has the opposite configuration from the one described anddepicted in the Figures.

Initially when the landing gear is down, and the upper drag brace 12 isin the extended position, shown in FIG. 2, the door is held closed.Numeral 40 indicates the closed door. FIGS. 5-7 show the same positionsof the landing gear and the double hook door mechanism as FIGS. 2-4however they include the door of the landing gear bay and a full view ofthe landing gear position relative to the landing gear bay.

As can be seen in FIG. 2, the door 40 is held closed due to the contactof the projection 14 on the lower hook 18 and in particular on the lowerhook portion 32.

As the landing gear begins to retract the upper drag brace including theprojection 14 begins to rotate counter-clockwise, as indicated at arrowC in FIG. 2. By way of this rotation, the projection 14 begins to moveout of the way of lower hook 18. The force of the springs 20 act on theupper hook 16 to pull in the direction of arrow F. The force of thespring 20 will pull at the connection point to upper hook 16 and willthereby force rotation of the upper hook 16 in a counter clockwisedirection, as indicated by arrow E. Once the projection 14 begins tomove out of the way of the lower hook 18 the lower hook 18 is free torotate. The force of the spring pulling the upper hook 16 in a counterclockwise rotation will in turn translate to a force pushing down on thelinkage rod 34 which, in turn, forces the lower hook 18 to rotate in aclockwise direction once it is free of the projection 14. This rotationwill transfer a load through the door rod 24 towards the door and thedoor will open, as shown in FIG. 3.

As the upper drag brace 12 and projection 14 continue to rotate in acounter clockwise direction, seen in FIG. 3, a position is reached atwhich the projection 14 is no longer contacting the lower hook and hasnot yet contacted the upper hook, i.e. it is free of the upper and lowerhooks 16, 18. At this point, the force of the springs 20 pulling theupper hook 16 in a counter clockwise rotation will cause it to rest onthe over-centre stop 42 indicated in FIG. 3. At this position the doorsare open and the over-centre stop 42 and the force of the springs 20will keep the doors from fluttering. It will be understood by a personskilled in the art that the over-centre stop 42 is connected to theairframe.

In this position, there is no connection between the double hook doormechanism 10 and the landing gear since neither of the upper or lowerhooks 16, 18 are connected to or abutting against the projection 14.

As the landing gear retracts into the landing gear bay the upper dragbrace 12 and the projection 14 will continue to rotate counterclockwise. This movement will eventually cause the projection 14 to comeinto contact with the upper hook 16. When the projection 14 comes intocontact with the upper hook 16 the continued counter clockwise movementof the upper drag brace 12 and projection 14 will cause the upper hook16 to begin to rotate clockwise, as indicated at arrow G in FIG. 4. Thismovement in turn will pull up the linkage rod 34 and in turn will causethe lower hook 18 to rotate in a counter clockwise direction, asindicated at arrow H in FIG. 4. The counter clockwise rotation of thelower hook 18 will pull the door rod 24 up, in the direction of arrow Iin FIG. 4 and in turn will pull the doors closed. In addition, theclockwise rotation of the upper hook 16 will stretch the springs 20 inthe direction of arrow J in FIG. 4.

At this point, the landing gear is in a fully retracted position withinthe landing gear bay and the bay doors are closed, as shown in FIG. 7.

When the landing gear is to be lowered the upper drag brace includingthe projection will begin to extend and to rotate in a clockwisedirection and the events described above will occur in reverse.

The rotation of the upper drag brace 12 and projection 14 in a clockwisedirection will begin to rotate the upper hook 16 in a counter clockwisedirection. This in turn will translate force to the linkage rod 34downwards, towards the lower hook 18 which in turn will force the lowerhook 18 to rotate in a clockwise direction. Clockwise rotation of thelower hook 18 will force the door rod 24 down towards the doors and willtherefore apply a force on the doors that will open them. At this stagethe landing gear bay doors will be open and the landing gear continuesto extend, as shown in FIG. 6.

As the landing gear continues to extend the projection will move out ofthe range of the upper hook 16 and will no longer be in contact with it.At this point the position illustrated in FIG. 3 is reached and is thesame as that described above with reference to FIG. 3.

With the continual extension of the landing gear, the projection 14 willeventually come into contact with the lower hook 18. When the projection14 connects with the lower hook 18 the clockwise rotation of the upperdrag brace 12 and projection 14 will force the lower hook 18 to rotatein a counter clockwise direction. This action will release the forceapplied to the door rod 24 and will therefore release the load appliedto the door and the door will close. At this point the landing gear isin its fully extended position and the landing gear door is closed, asshown in FIG. 5.

As stated above, existing landing gear may be retrofitted to include thedouble hook door mechanism of the present invention. It will beunderstood that in order to retrofit existing landing gear it will benecessary to modify the upper brace of the landing gear to include aprojection, such as the roller described above, in order for the hooksof the double hook door mechanism to connect with. The placement of theprojection will depend on the initial design of the landing gear and thelanding gear bay, including the geometry, door to tire timing and theloads and moment arms. A person skilled in the art will be able tocalculate the desired position of the projection on the landing gearbased on these requirements. It will also be understood that additionalmodifications may be required within the landing gear bay to ensure thatthe double hook door mechanism has sufficient space and clearance tooperate, as described herein, to open and close the doors.

While this invention has been described with reference to illustrativeembodiments and examples, the description is not intended to beconstrued in a limiting sense. Thus, various modifications of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thisdescription. It is therefore contemplated that the appended claims willcover any such modifications or embodiments. Further, all of the claimsare hereby incorporated by reference into the description of thepreferred embodiments.

Any publications, patents and patent applications referred to herein areincorporated by reference in their entirety to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

1. A landing gear door mechanism for use with an aircraft landing gear,the door mechanism comprising: a first connector connected to theaircraft airframe at a first connection point and configured to rotateabout the first connection point; a second connector, connected to thefirst connector and to the landing gear door and further connected tothe aircraft airframe at a second connection point, the second connectorconfigured to rotate about the second connection point; each of thefirst and second connectors being configured to independently rotateabout their relative connection points in opposing directions relativeto each other and configured to independently releasably connect withthe landing gear, the rotation of the first and second connectors andthe releasable connection of each connector to the landing gearproviding for the opening and closing of the landing gear door
 2. Thelanding gear door mechanism according to claim 1, wherein each of thefirst and second connectors are configured to independently releasablyengage with a projection on the landing gear.
 3. The landing gear doormechanism according to claim 2, wherein engagement of one of the firstor second connectors with the projection, during landing gear retractionand/or extension initiates rotation about the respective connector. 4.The landing gear door mechanism according to claim 1, wherein rotationof the first or second connector translates into rotation of the otherconnector about its connection point, the simultaneous rotation of thefirst and second connectors resulting in the opening or closing of theaircraft door.
 5. A device for opening and closing an aircraft landinggear bay door, comprising: a door rod coupled to the landing gear baydoor; a first connection means, pivotably coupled to the door rod at afirst end and pivotably coupled to the landing gear bay at a firstconnection point; a second connection means, coupled to the firstconnection means, and pivotably coupled to the landing gear bay at asecond connection point; the first and second connection meansconfigured to independently releasably connect with a pivot pointlocated on the landing gear.
 6. The device according to claim 5, whereinconnection of one of the first and second connection means with thepivot point during retraction and extension of the landing gear providesfor rotation of the first and second connection means providing forsimultaneous movement of the door rod to open or close the bay door. 7.The device according to claim 5, wherein the first and second connectionmeans each include hook means for connecting with the pivot point on thelanding gear.
 8. The device according to claim 5, wherein the secondconnection means is coupled to a biasing means that biases the secondconnection means to rotate in a first direction.
 9. A device for openingand closing a landing gear bay door comprising: a door rod coupled tothe landing gear bay door at a first end; a first connector, pivotablycoupled to the landing bay at a first connection point; a secondconnector, pivotably coupled to the landing bay at a second connectionpoint and coupled to the door rod at its second end; the first andsecond connectors coupled to each other and configured to simultaneouslyrotate in opposing directions, the first and second connectorsconfigured to independently engage with a projection located on thelanding gear, engagement of one of the first and second connectors withthe projection causing rotation of the connectors that translatesmovement to the door rod to open and close the landing gear bay door.10. The device according to claim 9, wherein the first and secondconnectors include hook members that are operable to releasably engagewith the projection.
 11. The device according to claim 9, wherein thefirst and second connectors are coupled to each other using a rod. 12.The device according to claim 9, wherein the first connector is biasedto pivot about the first connection point in a first direction.
 13. Thedevice according to claim 12, wherein the first connector is coupled toa spring to bias the rotation of the first connector about the firstconnection point in a first direction.